Reproducer for talking-machines.



tlhalllhl @AEN HENRY T. CRAPG, F BOSTON, MSSACHUSETTS.

REPRODCER FOR TALKING-MACHINES.

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Specification of Letters Patent.

Application led January 23, 1918. Serial No. 213,404.

- whereby a specially sensitive action is given to the needle as the latter followsv the grooves of the record, the said invention brieiiy described consisting of a. novel arrangement of a plurality of permanently magnetized points which act with a cushion ing or balancing effect upon the needle bar, in oppositionto the vibrating diaphragm.

For the purpose of explaining the said invention clearly, the annexed drawings have been provided, in which the Figure 1 is a plan view of a reproducerembodying the present improvement, looking down upon the vibrator diaphragm needle bar, and Fig. 2 is a transverse, sectional, view of the same taken on the line 2-2 of said Fig. 1. Fig. 4 is a relatively enlarged view of the magnetizedl spider 15 and of the needle bar located thereunder, 'and Fig. 3 is a transverse sectional View taken on the line 3-3 of said Fig. 4;

Referring to these drawings the numeral 10 indicates the sound box and 11 the vibrating diaphragm mounted in said box in the customary, or any other desired, manner. Journaled in bearings 12 formed on the sound box is the needle bar 13 whose inner end is turned inward and is'adapted to engage the diaphragm 1l as the needle bar is vibrated by engagement of the needle with the wave grooves of the record disk.

So far as I am aware the needle bar is customarily free to rock on or in its bearing l2, and' is governed' as to its movements,

solely by the said Wave grooves, no provision being made for balancing or cushioning the vibrating action of said needle bar and, by reason of such freedom of the needle and its bar there is an ocasional failure on the part of the needle to follow the Wave grooves and a blasting or unpleasant sound results.

Thisobjectionable result, I find by repeated experiment and demonstration, is overcome by means of my present improved balancing device which I will now describe. Secured to, or formed upon, the needle bar 13, near the inner end ot said bar, is a skele ton plate 14, which is here gular, and fixed to the sound box, immediately over the said' triangle, is a circular plate or spider 15. which is formed with inwardly projecting lingers or spurs 16 whose free end portions overlie the triangle 14 and are spaced apart from said triangle one .thirty 'second of an inch or therezibouts.

The lingers 16 are permanently magnetized and they therefore. operate constantly with a mild tendency tosteady the needle bar as to its vibratory movements andl to render such movements more reliable thus adding materially to the delicacy and warmth 'of tonal reproductions, particularly in reproducing quiet or low-toned passages, and also preventing the occasional unpleasant breaks and blasts caused by the needle jumping out of contact with the wave grooves ot the record.

It should be particularly noted that the center of the triangle 14 is immediately in register with the center of the inner end portion of the needle bar, and so that the influence of the several magnet points is equal ized on the said bar, thus balancing that end of the bar and in no degree tending to cramp it or to rock it laterally. Thilo I have adopted the described triangular form for the plate 14- it will be obvious that a plate of other -form could be used' with equally good results so long as the magnetic intluence is distributed equally around said plate.

The described balancing and steadying device adds practically'nothing to the cost ot reproducers yet itimproves materially the tonal eil'ects.

Having thus described* my invention .l claim in a reproducer comprising a sound box, a vibrating diaphragm, and a needle bar whose free end portion is adapted to engage said diaphragm, a plate formed on the said free end portion of the needle bar, a plural shown as tri anv ity oi' magnetized' spurs located adjacent to said plate and in opposition to the dia phragm.

TTENRY T. CRAPO. 

